Once a young high spirited youth in the real world with the powers of Superman, intense trauma had twisted his sense of justice and morals, exacerbated by the corrupted and ineffective heroes of post-Crisis Earth as well as his loss of his destiny as the "Universe's Greatest Protector".

During Blackest Night, but she is 'supposedly killed' off panel, but it is pretty heavily implied in a conversation with his parents and when she turns up with a broken arm with a black lantern ring at the end and Prime is shocked to see her alive.

I dunno I can kind of understand why they did it, but after they made a big deal of how much Prime loved Laurie and missed his parents and his Earth etc, etc, and trying to redeem Prime during LO3W it was kind of a dumb move.